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Foos Box

The Foos Box is a puzzle box from our Destiny Room at The Escapery in Marietta, GA . When we built this box and were testing it felt like we were playing Foosball hence the name Foos Box.

For those who are worried that they are going to ruin the puzzle by viewing this Instructable, no worries. The puzzle is in finding the rods, it is pretty self-explanatory on how to open by the symbol pairing. So lets get to it!

Step 1: Buy Stuff

Read through the complete instruction before purchasing your materials. There are some decisions regarding the material used to build the box and how you will want to finish it. You will want to make these decisions prior to dropping cash on materials.

Step 2: Test Setup

Unfortunately we didn't take any photos during construction and this is the only photo we have prior to staining/completion. Don't fret, the construction is fairly easy and is completely based on the size of the blocks in the channel and how far they have to travel.

Decide the Channel Block material and size. We used 2x4 segments roughly 10.5" long and they need to be long enough to accommodate the latching mechanism and something to keep the blocks from popping up out of the channel. When we get around to building 2.0 for when this one gets worn out we will use rails for cabinet draws to eliminate the need for cross straps.

Make a Test Channel. You want to determine the amount of travel you want and size of springs. Use a scrap piece of 2x4 and drill a half-inch hole to accommodate a dowel rod, this is the Hole Block. Make a Channel Block, we used a 2x4 cut to 10.5".. Affix the Hole Block to a sheet of plywood or a workbench. Create Channel Walls for the channel, they should be the same height as the Channel Block and at least 50% longer than it. Affix test Channel Walls on either side so that they are slightly wider than the width of the Channel Block for freedom of travel down the channel. Two business cards thickness is a good gap. You should now have two walls with a block at one end.

Test clearance and springs. Drill a wood screw on both sides of the hole on the Hole Block, leave the tapered head exposed and loop the end of a spring over the screw. You may want to tighten the screw down to be sure the spring stays on it, use a washer if your springs and screws are terribly mismatched. Drill wood screws in your Channel Block at spacing equal to your scrap block with the hold. Loop the other end of the springs to these screws and tighten if needed. Now use the dowel rod to push the block in the channel.

Record your measurements. Record the 'at rest' distance between the Hole Block and the Channel Block. Push the rod to the distance of springs travel (don't over do it) and record this distance. Make sure the difference is just longer than the width of the Lid Strap, the one from our picture is 1.5" wide. Take a scrap piece of 2x4 and affix it to the work surface at the limit of the travel. You've now made a boxed in channel for the Channel Block to travel on

Test the strap and bracket configurations. Now that you have the block limits physically established, you will need to mark the location of the Lid Strap, the T-bracket, and channel cross braces. Set the lid strap in the middle of the channel, you can temporarily affix it to the walls or add scrap blocks offset and screw the strap to them, use a washer to space the strap off the top of the walls. This is needed to simulate the clearance that will be present when the lid strap in in the lid. Next use washers to add the clearance needed to allow the t-bracket to slide over top the lid strap. The production version ended needing the T brackets to be doubled up so that they did not bend as easily when someone inevitably tried to force it open. Once you have this configured add in the cross straps over the channel. Test be sure that everything clears during the travel of the Channel Block. You may have to lengthen or shorten your channel block, use different springs, and play around with the location of straps before you get it down. Once you are satisfied with the setup record all of the dimensions.

Step 3: Build the Box Bottom

You now have your channel designed and all of the dimensions recorded which will allow you size the box.

Create Channel Blocks and Hole Blocks. You will need 4 sets of Channel Blocks and Hole Blocks based on the sizes you used for the Test Setup. Go ahead and drill the ½” holes in the Hole Blocks.

Create Channel Walls. Cut 5 Channel Walls, they should be as long as the full channel including the Hole Block and need to be as tall as or slightly taller than the height of the Channel Blocks. They should touch the left and right walls of the Box Bottom. We used pine board which is not the best choice and we recommend using MDF.

Determine interior dimensions. Layout the 4 Channel blocks, 4 Hole Blocks, and 5 Channel Walls. This will give you the length and width of the interior of the box

Create the Walls for the Bottom Box. These should be the same height as the Channel Walls. Again we used pine board and we would recommend MDF.

Cut out the Bottom of the Box. We would suggest using mdf instead of plywood, don't worry about what the bottom looks like because this beast needs to be screwed into whatever surface it rests on.

Dry Assemble the Bottom Box. Take all the components from above and assemble it all using clamps to keep the Walls and Channel walls in place. Use a spacer between the Channel Walls and the Channel Blocks to allow for travel. Two business cards together make a good sized gap. Mark where the Hole Blocks line up with the Walls. You will need this to drill the ½” holes in the walls.

Drill holes in Walls. Using the marks made during the Dry Assembly, clamp the Hole Block on the Wall as a guide and drill the holes into the Walls. Using a drill press is best but you can get away with a drill if you have a steady hand.

Assemble the Bottom Box. Attach the Walls to the Bottom of the Box. Then attach the Hole Block and Channel Walls to the Walls and Bottom of the Box. Use the Channel Blocks and the spacers from step 6 to be sure the Channel Walls to be sure you have proper alignment. Wood screws, wood glue, and braid nails are a good combination for a strong attachment.

Screws and Springs. Drill the wood screws into the Hole Block and Channel Blocks. Put the springs in for each block and test the travel using the dowel rod. You may have to do some sanding to keep the travel smooth.

Temporarily install the Lid strap. Use clamps or screws to get the Lid Strap affixed directly down the middle of the box. This is your guide for installing the T braces that will slide over them. Again be sure to use a washer under every point of contact with the box to account for the screws that will be used to affix the strap and just for tolerance.

Install the T Braces. Use washers or scrap metal banding material to install the T Brace so it slides over the Lid Strap when the springs are at rest and clears it completely when the push rod extends the spring. Again we ended up using two of them on top of each other for the rear channel to keep the web part of the T from bending up when someone improperly tries to open it.

Install the cross straps. Screw in a strap in the front and rear of the channel block. The strap on the side of the channel block not touched by the dowel rod should cover it both at rest and at extension. Mark the alignment of the Lid Strap with the Bottom Box Walls. Take up the temporary Lid Strap and proceed to assembling the Box Top.

Step 4: Build the Box Top

You now have the Bottom Box assembled and will use the dimensions to create the Box Top.

Size the height of the Box Top. We built our box to accommodate a set of rods and a letter sized document needed for other puzzles. Using that criteria the interior height of the Box Top was 5.5”. Think about what you would want to hid in the lid, that it will have to sit horizontally and vertically without falling out. This will determine the height for your box.

Cut the Walls for the Box Top. We used Pine Board for our box however we would suggest MDF because of how square and inert the materials is.

Cut the Box Top Lid. We used Plywood for our box however as above we suggest MDF.

Assemble the Box Top. Attach the Walls to the Box Top Lid. Again wood screws, glue, and braid nails in combination are swell.

Create the Lid Strap. Use the markings from the Box Bottom to mark the location for the strap. The strap should be longer than the interior length so you can fold the strap 90 degrees at the edges. Use a hammer and a vise to get the strap bent 90 degrees at each end. Be sure to bend one end and fit it in the lid to be sure you get a proper mark before bending the other. Do not attach the Lid Strap yet.

Cut the Dowels. Dry fit the Lid Strap into the Box Top and measure the distance to the lid. Be sure that the Lid Strap is as flush with the open frame as possible so it does not interfere with closing the box when assembled. Use the 1.5” dowels and cut three sections with the measurement taken.

Prep Dowels. The center of the dowels should line up with the 3 Channel Walls separating the 4 channels. Mark the locations on the inside of the box lid and drill the pilot holes through. Use a countersink bit so that the screw heads will be flush with the lid. Drill a pilot hole in the center of one end for the 3 dowels.

Attach the Lid Strap. Now that you have the pilot holes for the lid you should attach the Lid Strap to the Box Top. Use the screw holes in the strap to run wood screws into the walls. If you want some additional points of attachment drill pilot holes in the metal strap.

Attach the Dowels. Slip the dowel rods in between the Lid Strap and the top of the box with the pilot hole end against the lid. Line them up with the pilot hole on the lid and screw them in from the outside. If they are not perfectly perpendicular to the lid don’t worry because the Lid Strap will pull them in line.

Attach to Lid Strap. One at a time get the Dowels lined up with the Lid Strap and drill through the metal strap and into the Dowel. Use a wood screw to attach them securely.

Step 5: Put It All Together and Test

Now that you've built the Box Top and Bottom, time to put the together and make sure it all works.

Install the Hinge. Unhook the springs from the Channel Blocks so they can be pushed to the full extension so the T-Brace doesn't press against the Lid Strap. Use clamps to put the Box Top and Box Bottom together. A have snug but not wood straining clamp on all four corners. If you have a gap it is most likely the screw heads affixing the dowel to the Lid Strap. Measure and drill a countersink in the Channel Wall. If it is still not tight check to see if your cross straps are touching the Lid Strap, move the cross strap as needed. Your piano hinge should run almost the entire length of the box which will require you to cut the piano hinge. Use a rotary tool to make the cut on the hinge. Center the hinge between the boxes and carefully screw them in.

Open and Close. Take of your clamps and be sure the box opens and closes. you may have to adjust the hinge slightly and check again for any straps or screws keeping it from a tight seal.

Push Rods. Cut four dowel rods, using our design they should be about 8" long.

Test locking. Hook the springs back up to the Channel Blocks. Gently close the lid, it will be resting on top of the rear T-Brace. Push all four rods in at the same time and release. It really helps to have an assistant for this part. All four Channel Blocks should spring back when you stop pushing. They will probably get caught and need adjustment.

Fine Tuning. Now you must ensure that the T-Braces easily slid over the Lid Strap and that you have a tight seal on the lid. You may have to adjust these items

T-Braces - adjust them up or down using washers/spacers to have a workable fit over the Lid Strap. You may have to sand the end of the web on the T-brace to help it not catch against the Lid Strap.

Cross Straps - These may need to be moved around so that you keep the Channel Blocks in the channels while not interfering with the travel of the Channel Block/T-Brace.

Cleaning - be sure the channels are free of dust and debris.

Channel Block - We ended up affixing metal strap scraps to the blocks to make up for gaps between the cross straps and the top of the block.

Step 6: Make It Pretty

To be used in our escape room it had to be a visually pleasing element that ties into the story. We used a Roman Theme from the laurels on the top to the deer and Olive branches on the front. We used an American Walnut gel stain from Varathane sold at Home Depot.

Stain. if you used MDF you will need to apply a veneer. Otherwise you can stain your box after proper sanding. We also stained the rods

Decoration. we printed patterns onto card stock and cut them out with a razor. We taped them to the box and painted them in with brown acrylic art paint. We ordered themed cabinet pulls and screwed them into the ends of the push rods.

Finish - we used a Satin Polyurethane finish on the box exterior and the push rods. We did 3 coats sanding lightly between each.